[magick-users] Compositing using DissolveCompositeOp

[Anthony Thyssen]

Elie Zedeck RANDRIAMIANDRIRAY on  wrote...
| Hi guys,
| 
| I couldn't find in the Documentation any ways to use the 
| DissolveCompositeOp, as normally, it requires a parameter for the 
| dissolve factor.
| 
| Anyone knows how to do this?
| 
The parameters are passed as part of the geometry specification in the
MagickCore library API.

It is generally not used directly like this but from API specific
interfaces.

In actual working it is equivelent to overlaying two images that have had their
alpha channel multiplied by the appropriate dissove percentages.

See  http://www.imagemagick.org/Usage/compose/#dissolve

The BlendCompositeOp is the same except instead of Over,  Plus
is used instead, to provide a Weighted Addition, or interpolation
between the images.

See  http://www.imagemagick.org/Usage/compose/#blend

However it is also designed to allow Extrapolation basied on the input
percentages, whcih is not posible by simply pre-multiplying each images
alpha channel values.

The -unsharp operator for example is a Extrapolated Blend of the
original image and a blurred copy of the original image.

see  http://www.imagemagick.org/Usage/#blend_use

  Anthony Thyssen ( System Programmer )    <A.Thyssen at griffith.edu.au>
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    The Definition of an Upgrade: Take old bugs out, put new ones in.
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